In an interview with NPR on Tuesday, the chairman of the Joint Chiefs of Staff says he's never picked up on those feelings from the White House.

In his book, Duty, Gates says President Obama was distrustful of the military and its motives, complaining the military was trying to box him in on sending more troops to Afghanistan. Dempsey sees it differently.

"I have never questioned whether the National Security staff, the president of the United States or the vice president trusted me," Dempsey said. "I always felt that they would tell me if they didn't. I can't speak for why Secretary Gates felt that way, I do not."

Gates recommended Dempsey for the top military job before retiring in 2011. Dempsey says he hopes the book will spark a discussion about the relationship between military and civilian leaders.

Update at 7:50 p.m. ET: More From Dempsey

In his new memoir, Gates says that when soldiers put their lives on the line, they need to know the commander-in-chief believes in their mission.

The quality Gates missed in Obama was passion. And where this passion mattered most, he wrote, was in Afghanistan.

"Passion is an odd way to put it — and again, I'm not criticizing the book," Dempsey said. "I have seen emotion in the president, [he] genuinely feels the loss of service men and women. I certainly recognize in him that he feels a responsibility as commander-in-chief."

Dempsey says Gates has tapped into a broader issue: that democracies have difficulty staying focused on prolonged wars.